This document shows how to configure dialout using a modem with the NM-AM analog modem network module. In this scenario, a router with the NM-8AM modem module dials the Primary Rate Interface (PRI) of the central site router.

This document assumes you have a good understanding of the various issues associated with modem configurations. If you need more information on these issues, please refer to the Modem-Router Connection Guide.

In this 3600 chassis, the NM-8AM card is installed in slot 3. Referring to How Async Lines are Numbered in Cisco 3600 Series Routers document, we ascertain that slot 3 has line 97 through 128 reserved. To determine which specific async interface you should configure, use the show line command to find out the available lines. In this configuration, note that only lines 97-104 (8 lines) are available within that range. Hence, to configure the first modem in the card configure line 97 (and interface async97) while the last modem is line/async104.

Verify the configuration of the modem. You should check both the line configuration corresponding to the modem as well as the interface async.

Reverse telnet to the modem and initiate a dialout.

Reverse telnet out the port to the modem, and use the AT command set to dial and connect to the remote device. This can be used to verify that the modem hardware and telephone circuit are functioning. In this example, since the modem port is on line 104, reverse telnet to port 2104 on the router. For more information on reverse telnets, refer to Establishing a Reverse Telnet Session to a Modem.

Use the start-chat command in order to activate the chat script and initiate a dial. The start-chat command requires you to specify the name of the chat script to be activated, the phone number to be dialed, and the modem interface to dial out on.

Verify that there is a route to the async interface.

Use the show ip route command in order to check whether there is a route to the async interface. If there is no route, create a static route. An example is shown:

ip route 10.10.0.1 255.255.255.255 Async104

Generate a ping destined for the next-hop network specified in step 4.

A ping for the remote router, which is specified using the next-hop network from step 4, causes the router to dial the remote device.

Verify that the chat script name is identical to the one specified in the dialer map statement. Also verify that the phone number to be dialed is correctly specified.

Check to see that interesting traffic is correctly defined. Interesting traffic is specified with the dialer-list command.

Ensure that the interesting traffic definition is applied to the async interface. This is done using the dialer-group command, where the group number must match the interesting traffic definition specified with the dialer-list command.

Verify that the username and passwords for PAP/CHAP authentication are correct.

Check to make sure that the dialer map statement has the correct name, IP address, and phone number to dial.

debug dialer - To display debugging information about the packets received on a dialer interface. When Dial on Demand Routing (DDR) is enabled on the interface, information concerning the cause of any call (called the dialing cause) is also displayed. For more information, see the debug dialer information in the Debug Commands documentation.

debug modem - To display the modem line activity, modem control, and process activation messages on the router.

debug ppp negotiation - To display information on PPP traffic and exchanges while negotiating the PPP components including Link Control Protocol (LCP), authentication, and Network Control Protocol (NCP). A successful PPP negotiation will first open the LCP state, then authenticate, and finally negotiate NCP.